CFI: Do not use uninitialized cmd_reset

Do not use uninitialized cmd_reset; issue both AMD and Intel reset
commands instead

From a short test, it looks like AMD-style flash roms treat *any* unknown
command write as a reset, at least when in CFI Query mode, so issuing the
Intel reset command to AMD-style flashs seems safe (from the small sample I
have), plus the 3-cycle magic sequence should kick the state machine into
the right state even without a reset command. Since the AMD-style flashs
require the unlock sequence for real operation, I chose to try the AMD reset
command first, so that Intel flashs do no see an invalid command prior to
the CFI query.

I have tested the patch on AM29LV320-style flashs from Fujitsu and Macronix,
plus Intel StrataFlash.

Signed-off-by: Michael Schwingen <michael@schwingen.org>
Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index eb509f55571a4cf3d9fc60511f3c3c579dd955da..439c950cf22837b8874887a010189b3b5ccd5f32 100644 (file)
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -1538,7 +1538,12 @@ static int __flash_detect_cfi (flash_info_t * info, struct cfi_qry *qry)
 {
        int cfi_offset;
 
-       flash_write_cmd (info, 0, 0, info->cmd_reset);
+       /* We do not yet know what kind of commandset to use, so we issue
+          the reset command in both Intel and AMD variants, in the hope
+          that AMD flash roms ignore the Intel command. */
+       flash_write_cmd (info, 0, 0, AMD_CMD_RESET);
+       flash_write_cmd (info, 0, 0, FLASH_CMD_RESET);
+
        for (cfi_offset=0;
             cfi_offset < sizeof(flash_offset_cfi) / sizeof(uint);
             cfi_offset++) {